/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.util;

import ch.qos.logback.core.Context;
import ch.qos.logback.core.CoreConstants;
import ch.qos.logback.core.spi.ContextAware;
import ch.qos.logback.core.spi.LifeCycle;
import ch.qos.logback.core.status.OnConsoleStatusListener;
import ch.qos.logback.core.status.StatusListener;

public class StatusListenerConfigHelper {

  public static void installIfAsked(Context context) {
    String slClass = OptionHelper.getSystemProperty(CoreConstants.STATUS_LISTENER_CLASS);
    if (!OptionHelper.isEmpty(slClass)) {
      addStatusListener(context, slClass);
    }
  }

  private static void addStatusListener(Context context, String listenerClassName) {
    StatusListener listener = createListenerPerClassName(context, listenerClassName);
    initAndAddListener(context, listener);
  }

  private static void initAndAddListener(Context context, StatusListener listener) {
    if (listener != null) {
      if (listener instanceof ContextAware) // LOGBACK-767
        ((ContextAware) listener).setContext(context);

      boolean effectivelyAdded = context.getStatusManager().add(listener);
      if (effectivelyAdded && (listener instanceof LifeCycle)) {
        ((LifeCycle) listener).start(); // LOGBACK-767
      }
    }
  }

  private static StatusListener createListenerPerClassName(Context context, String listenerClass) {
    try {
      return (StatusListener) OptionHelper.instantiateByClassName(listenerClass, StatusListener.class, context);
    } catch (Exception e) {
      // printing on the console is the best we can do
      e.printStackTrace();
      return null;
    }
  }

  /**
   * This utility method adds a new OnConsoleStatusListener to the context
   * passed as parameter.
   *
   * @param context
   * @since 1.0.1
   */
  static public void addOnConsoleListenerInstance(Context context, OnConsoleStatusListener onConsoleStatusListener) {
    onConsoleStatusListener.setContext(context);
    boolean effectivelyAdded = context.getStatusManager().add(onConsoleStatusListener);
    if (effectivelyAdded) {
      onConsoleStatusListener.start();
    }
  }

}
